[Federal Register Volume 59, Number 77 (Thursday, April 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-8055]


[[Page Unknown]]

[Federal Register: April 21, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-NM-158-AD; Amendment 39-8870; AD 94-07-12]

 

Airworthiness Directives; Jetstream Model ATP Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to Jetstream Model ATP series airplanes, that requires 
inspections to detect fatigue-related cracking and loose rivets in the 
subframe yoke assemblies of the quick engine change units (QECU) on 
both wings; replacement of rivets; and repair or replacement of yoke 
assemblies, if necessary. This amendment is prompted by in-service and 
fatigue test reports of cracking in the yoke of a QECU subframe. The 
actions specified by this AD are intended to prevent loss of structural 
integrity of the engine mount.

DATES: Effective May 23, 1994. -
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of May 23, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Jetstream Aircraft, Inc., P.O. Box 16029, Dulles 
International Airport, Washington, DC 20041-6029. This information may 
be examined at the Federal Aviation Administration (FAA), Transport 
Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, 
Washington; or at the Office of the Federal Register, 800 North Capitol 
Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue SW., Renton, Washington 98055-4056; telephone (206) 
227-2148; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations to include an airworthiness directive (AD) that is 
applicable to Jetstream Model ATP airplanes was published in the 
Federal Register on November 1, 1993 (58 FR 58305). That action 
proposed to require inspections to detect fatigue-related cracking and 
loose rivets in the subframe yoke assemblies of the quick engine change 
units (QECU) on both wings; and replacement of rivets, and repair or 
replacement of yoke assemblies, if necessary.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter supports the proposal.
    Since the issuance of the proposal, Jetstream Aircraft Limited as 
issued Service Bulletin ATP-54-11, Revision 1, dated November 9, 1993. 
This revision is substantially the same as the original version. 
However, it contains procedures that would allow operators to perform a 
visual inspection, rather than an eddy current inspection, prior to 
reassembly of an engine to the QECU subframe, or prior to installation 
of an already assembled engine and QECU unit on an airplane, if the 
subframe unit has accumulated less than 500 hours time-in-service since 
the last eddy current inspection. This new provision is relieving in 
nature in that operators would not be required to perform an extensive 
and costly eddy current inspection, if one had been performed only 
shortly beforehand. The FAA has revised the final rule to include such 
a provision, and to include reference to the new revision of the 
service bulletin as an additional source of appropriate service 
information.
    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule with the change previously 
described. The FAA has determined that this change will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.
    The FAA estimates that 10 airplanes of U.S. registry will be 
affected by this AD, that it will take approximately 3 work hours per 
airplane to accomplish the required actions, and that the average labor 
rate is $55 per work hour. Based on these figures, the total cost 
impact of the AD on U.S. operators is estimated to be $1,650, or $165 
per airplane.
    The total cost impact figure discussed above is based on 
assumptions that no operator has yet accomplished any of the 
requirements of this AD action, and that no operator would accomplish 
those actions in the future if this AD were not adopted.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 14 CFR part 
39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

94-07-12 Jetstream Aircraft Limited: Amendment 39-8870. Docket 93-
NM-158-AD.

    Applicability: All Model ATP airplanes, certificated in any 
category.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent loss of engine mount structural integrity, accomplish 
the following:
    (a) Within 750 hours time-in-service after the effective date of 
this AD, perform a detailed close visual inspection to detect 
cracking and loose rivets in the subframe yoke assemblies of the 
quick engine change units (QECU) on the left- and right-hand wings, 
in accordance with Jetstream (BAe) ATP Service Bulletin ATP-54-11, 
dated July 13, 1993; or Revision 1, dated November 9, 1993.
    (1) If any loose rivet is detected: Prior to further flight, 
replace the existing rivet with a new or serviceable rivet in 
accordance with the service bulletin.
    (2) If any type ``A'' cracking (as defined in the service 
bulletin) is detected having a crack length that is less than or 
equal to 4 rivet pitches: Repeat the inspection thereafter at 
intervals not to exceed 250 hours time-in-service.
    (3) If any type ``A'' cracking (as defined in the service 
bulletin) is detected having a crack length that is greater than 4 
rivet pitches, or that is less than or equal to 7 rivet pitches: 
Repeat the inspection thereafter at intervals not to exceed 35 hours 
time-in-service.
    (4) If any type ``A'' cracking (as defined in the service 
bulletin) is detected having a crack length that is greater than 7 
rivet pitches: Prior to further flight, repair in accordance with a 
method approved by the Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate.
    (5) If any type ``B'' or ``C'' cracking (as defined in the 
service bulletin) is detected: Prior to further flight, repair in 
accordance with a method approved by the Manager, Standardization 
Branch, ANM-113, FAA, Transport Airplane Directorate.
    (b) Except as provided by paragraph (c) of this AD: Prior to 
each reassembly of the engine to the QECU subframe, and prior to 
installation of an already assembled engine and QECU subframe unit 
on an airplane, perform an eddy current inspection to detect 
cracking of the subframe yoke assembly, in accordance with Jetstream 
(BAe) ATP Service Bulletin ATP-54-11, dated July 13, 1993; or 
Revision 1, dated November 9, 1993. Prior to further flight, replace 
any cracked subframe yoke assembly with a new or serviceable 
subframe yoke assembly in accordance with the service bulletin.
    (c) For QECU subframe units that have accumulated less than 500 
hours time-in-service since an eddy current inspection has been 
conducted in accordance with paragraph (b) of this AD: Prior to 
reassembly of the engine to the QECU subframe, and prior to 
installation of an already assembled engine and QECU subframe unit 
on an airplane, perform a detailed close visual inspection to detect 
cracking of the subframe yoke assembly, in accordance with Paragraph 
2.A. of the Accomplishment Instructions of Jetstream (BAe) ATP 
Service Bulletin ATP-54-11, Revision 1, dated November 9, 1993. 
Prior to further flight, replace any cracked subframe yoke assembly 
with a new or serviceable subframe yoke assembly in accordance with 
the service bulletin.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Standardization Branch, ANM-113, 
FAA, Transport Airplane Directorate. Operators shall submit their 
requests through an appropriate FAA Principal Maintenance Inspector, 
who may add comments and then send it to the Manager, 
Standardization Branch, ANM-113.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (e) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the airplane to a location where the 
requirements of this AD can be accomplished.
    (f) The inspections and replacements shall be done in accordance 
with Jetstream (BAe) ATP Service Bulletin ATP-54-11, dated July 13, 
1993; or Jetstream (BAe) ATP Service Bulletin ATP-54-11, Revision 1, 
dated November 9, 1993, which incorporates the following list of 
effective pages:

------------------------------------------------------------------------
                    Revision level shown on                             
    Page No.                 page                 Date shown on page    
------------------------------------------------------------------------
1, 3, 5           1.........................  November 9, 1993.         
2, 4, 6-9         Original..................  July 13, 1993.            
------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
Part 51. Copies may be obtained from Jetstream Aircraft, Inc., P.O. 
Box 16029, Dulles International Airport, Washington, DC 20041-6029. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (g) This amendment becomes effective on May 23, 1994.

    Issued in Renton, Washington, on March 30, 1994.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 94-8055 Filed 4-20-94; 8:45 am]
BILLING CODE 4910-13-U